The invention relates particularly to a gas dosimeter in a holding means with a clip for fastening to the user's clothes, containing a diffusion indicator tube with a predetermined breaking point for opening.
By means of the gas dosimeter, diffusion test or indicator tubes are brought into contact with the ambient atmosphere. The test air is not transported into the test tube by a transporting means such as a pump, but automatically by diffusion. The discoloration in the indicator tube, in conjunction with the testing period, is then a measure of the concentration of the gas to be detected.
One know colorimetric gas dosimeter contains a dosimeter tube disposed in a transparent retaining tube. The dosimeter tube, with a color indicator for the gas to be detected, is fused shut at both ends when shipped by the factory. To open it, it has a break line in the vicinity of one end. The larger, transparent retaining tube is made of an unbreakable plastic. At one open end it has a clip for fastening it to the user's clothes. The other end can be closed by an elastic stopper having an axial recess in which the end remote from the break line of the dosimeter or indicator tube is received.
Prior to use, the receiving stopper with the dosimeter tube are withdrawn from the retaining tube, the free ends of the dosimeter tube are broken off at the break line and, in an open state, it is again inserted into the retaining tube. The color indicator then protrudes over the opening of the dosimeter tube, and the open end of the retaining tube communicates with the ambient air so that the gas to be detected can diffuse therein. The coloration is a measure of the absorbed amount (German OS No. 31 367 756).
To avoid possible injuries from glass splinters, hands and face must be protected. This makes the use difficult or, under careless handling, even dangerous (MSA Dosimeter Tubes, Instructions for Detecting Nitrogen Dioxide using Nitrogen Dioxide Dosimeter, part No. 469414).